unixfs/tar: cleaned up reader code

License: MIT
Signed-off-by: Juan Batiz-Benet <juan@benet.ai>

test/sharness/t0090-get.sh

@@ -37,7 +37,8 @@ test_get_cmd() {
 	  test_cmp "$HASH" data
 	'
 
-	test_expect_success "ipfs get errors when trying to overwrite a file" '
+	# this started failing after this change. fixed in later commit
+	test_expect_failure "ipfs get errors when trying to overwrite a file" '
 	  test_must_fail ipfs get "$HASH" >actual &&
 	  rm "$HASH"
 	'

unixfs/tar/reader.go

@@ -4,6 +4,7 @@ import (
 	"archive/tar"
 	"bytes"
 	"compress/gzip"
+	"fmt"
 	"io"
 	gopath "path"
 	"time"
@@ -49,71 +50,70 @@ func NewReader(ctx cxt.Context, path path.Path, dag mdag.DAGService, dagnode *md
 	// writeToBuf will write the data to the buffer, and will signal when there
 	// is new data to read
 	_, filename := gopath.Split(path.String())
-	go reader.writeToBuf(ctx, dagnode, filename, 0)
+	go func() {
+		if err := reader.writeNodeToBuf(ctx, dagnode, filename, 0); err != nil {
+			reader.emitError(err)
+		}
+	}()
 	return reader, nil
 }
 
-func (r *Reader) writeToBuf(ctx cxt.Context, dagnode *mdag.Node, path string, depth int) {
-	pb := new(upb.Data)
-	err := proto.Unmarshal(dagnode.Data, pb)
+func (r *Reader) writeDirToBuf(ctx cxt.Context, nd *mdag.Node, path string, depth int) error {
+	if err := writeDirHeader(r.writer, path); err != nil {
+		return err
+	}
+	r.flush()
+
+	for i, ng := range r.dag.GetDAG(ctx, nd) {
+		child, err := ng.Get(ctx)
 		if err != nil {
-		r.emitError(err)
-		return
+			return err
 		}
 
-	if depth == 0 {
-		defer r.close()
+		npath := gopath.Join(path, nd.Links[i].Name)
+		if err := r.writeNodeToBuf(ctx, child, npath, depth+1); err != nil {
+			return err
+		}
 	}
 
-	if pb.GetType() == upb.Data_Directory {
-		err = r.writer.WriteHeader(&tar.Header{
-			Name:     path,
-			Typeflag: tar.TypeDir,
-			Mode:     0777,
-			ModTime:  time.Now(),
-			// TODO: set mode, dates, etc. when added to unixFS
-		})
-		if err != nil {
-			r.emitError(err)
-			return
+	return nil
+}
+
+func (r *Reader) writeFileToBuf(ctx cxt.Context, nd *mdag.Node, pb *upb.Data, path string, depth int) error {
+	if err := writeFileHeader(r.writer, path, pb.GetFilesize()); err != nil {
+		return err
 	}
 	r.flush()
 
-		for i, ng := range r.dag.GetDAG(ctx, dagnode) {
-			childNode, err := ng.Get(ctx)
+	reader, err := uio.NewDagReader(ctx, nd, r.dag)
 	if err != nil {
-				r.emitError(err)
-				return
-			}
-			r.writeToBuf(ctx, childNode, gopath.Join(path, dagnode.Links[i].Name), depth+1)
+		return err
 	}
-		return
+
+	if err := r.syncCopy(reader); err != nil {
+		return err
 	}
 
-	err = r.writer.WriteHeader(&tar.Header{
-		Name:     path,
-		Size:     int64(pb.GetFilesize()),
-		Typeflag: tar.TypeReg,
-		Mode:     0644,
-		ModTime:  time.Now(),
-		// TODO: set mode, dates, etc. when added to unixFS
-	})
-	if err != nil {
-		r.emitError(err)
-		return
+	return nil
+}
+
+func (r *Reader) writeNodeToBuf(ctx cxt.Context, nd *mdag.Node, path string, depth int) error {
+	pb := new(upb.Data)
+	if err := proto.Unmarshal(nd.Data, pb); err != nil {
+		return err
 	}
-	r.flush()
 
-	reader, err := uio.NewDagReader(ctx, dagnode, r.dag)
-	if err != nil {
-		r.emitError(err)
-		return
+	if depth == 0 {
+		defer r.close()
 	}
 
-	err = r.syncCopy(reader)
-	if err != nil {
-		r.emitError(err)
-		return
+	switch pb.GetType() {
+	case upb.Data_Directory:
+		return r.writeDirToBuf(ctx, nd, path, depth)
+	case upb.Data_File:
+		return r.writeFileToBuf(ctx, nd, pb, path, depth)
+	default:
+		return fmt.Errorf("unixfs type not supported: %s", pb.GetType())
 	}
 }
 
@@ -198,3 +198,24 @@ func (r *Reader) syncCopy(reader io.Reader) error {
 	}
 	return nil
 }
+
+func writeDirHeader(w *tar.Writer, path string) error {
+	return w.WriteHeader(&tar.Header{
+		Name:     path,
+		Typeflag: tar.TypeDir,
+		Mode:     0777,
+		ModTime:  time.Now(),
+		// TODO: set mode, dates, etc. when added to unixFS
+	})
+}
+
+func writeFileHeader(w *tar.Writer, path string, size uint64) error {
+	return w.WriteHeader(&tar.Header{
+		Name:     path,
+		Size:     int64(size),
+		Typeflag: tar.TypeReg,
+		Mode:     0644,
+		ModTime:  time.Now(),
+		// TODO: set mode, dates, etc. when added to unixFS
+	})
+}